Most graphs of polling data show shifts that are very gradual. (Tracking real-time changes in poll results often is about as exciting as watching paint dry.) Recently, however, the HuffPost Pollster website produced a graph of national polling on Congress that showed one of the most dramatic shifts I've ever seen in 40 years of involvement in politics. It charts responses to the question of whether voters would like Republicans or Democrats to control the House.

The year began with Democrats 8 points ahead of Republicans on the generic congressional ballot test, 46 percent to 38 percent. The GOP had come out of the 2012 elections licking its wounds, having lost a presidential election that, just a year earlier, appeared highly winnable. As the year progressed, the Democratic advantage gradually but consistently declined, paralleling a similar erosion of President Obama's job-approval rating since his reelection. The drop in Democrats' numbers leveled off in June, to a statistically insignificant 1 percentage point lead over Republicans. It is important to remember that there is a historic tendency for this poll question to skew by a couple of points in favor of Democrats, making that meager edge almost certainly an illusion.

Then, in August, statements started coming from some of the more exotic Republicans in the House and Senate that perhaps it was a good idea to shut down the government over the implementation of the Affordable Care Act. Notwithstanding warnings from House and Senate Republican leaders and experienced (and wiser) members that such an effort would be a disaster for the party, the Republicans in the "kamikaze caucus" barreled ahead, over the cliff, shutting down the government.

Sure enough, the Democratic numbers in the generic ballot began to pull dramatically ahead, resembling a steep ascent up the side of a mountain, ending about 7 points ahead of Republicans, 45 percent to 38 percent—an advantage that, were it to last until the election, would give Democrats a chance to recapture the House.

Then, in mid-October, the focus shifted from the government-shutdown fiasco to a different debacle, this time a Democratic disaster: the botched launch of the Obamacare website and subsequent implementation problems of the health care law, including termination notices going out to many people who had insurance coverage. The Democratic numbers from the generic-ballot test dropped from 45 percent to 37 percent, and Republicans moved up to 40 percent. This 10-point net shift from a Democratic advantage of 7 points to a GOP edge of 3 points in just over a month is breathtaking, perhaps an unprecedented swing in such a short period. Occurring around Election Day, such a shift would probably amount to the difference between Democrats picking up at least 10 House seats, possibly even the 17 needed for a majority, and instead losing a half-dozen or so seats.

Of course, with the election 11 months away, it's too early to get really excited about this turnabout, but it demonstrates the volatility we are seeing these days in American politics. It must also give Democrats a sense of déjà vu, back to when the bottom fell out for them during the 2009-10 fight over passage of the Affordable Care Act. In that case, though, they suffered a gradual decline in party fortunes, starting in the summer of 2009 and culminating in the loss of 63 seats and the House majority in November 2010—the biggest drop in House seats for either party since 1948 and the largest in a midterm election since 1938. Democrats didn't fare much better in the Senate, losing six seats.

No one knows for sure how the next few phases of ACA implementation will go. Democrats' hopes that their fortunes will improve as a result of upcoming fiscal debates are starting to look pretty shaky, however. Democrats may be counting on Republicans to engage in more self-destructive behavior when government funding expires in mid-January and the debt ceiling expires in February.

But it looks increasingly likely that Republicans will go along with a deal, averting a spending/debt-ceiling crisis, and not repeat the disaster of this fall. Avoiding such a fight would keep most of the public's focus on Obamacare, and, in Republicans' eyes, give them the gift that will keep on giving. At this point, that doesn't appear to be an unrealistic expectation.

But what will happen next? A jaded observer might suggest that certain Senate Democrats may try to move the goalposts of a budget deal, pushing for additional Republican concessions to the point that House Speaker John Boehner can't deliver enough of the hard-liners in his caucus, thus creating a repeat of last fall's showdown. Of course, that is a highly cynical view, but it does not seem implausible that Senate Majority Leader Harry Reid might try such a strategy. The catch is whether Democrats could potentially sabotage a budget deal without leaving any incriminating fingerprints. The cynics might be wrong but, then again, Reid has six Senate seats up next year in states that Mitt Romney carried by double-digit margins. We'll see.

This article appears in the December 7, 2013, edition of National Journal Magazine

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